The present invention relates to a method and an apparatus for inspecting appearance and shape of a subject body such as a tire, a tire component or the like.
A tire, for example, is judged whether it is suitable as a product regarding the circularity and state of the surface such as unevenness, discoloration, contamination, flaws and the like.
Generally, it has been carried out to take a picture of a subject body to obtain appearance data and judge quality of the subject body by a state of the surface decided from the appearance data.
Otherwise, in a tire inspection apparatus disclosed in Japanese Laid-Open Patent Publication Hei 11-138654, a slit light is projected on a tire surface and a picture of the surface is taken by an area camera.
Picture data taken by the area camera are processed by optical cutting method which analyzes a shape with a slit light, and the shape of the tire is re-constituted to be used for judgment of quality of the tire.
However, according to the appearance data taken by the line camera, circularity and unevenness of a surface can not be judged correctly, though discoloration and contamination can be judged, and according to the shape data taken by the area camera, discoloration and contamination can not be judged, though circularity, unevenness of a surface and a flaw can be judged.
If either of the appearance data and the shape data is used, there occurs a delicate borderline case that judgment is difficult so that sometimes a good article is judged as a no-good article and vice versa and accuracy of the judgment is low.
The present invention has been accomplished in view of the foregoing, and an object of the invention is to provide a method and an apparatus for inspecting appearance and shape of a subject body, in which installation cost and installation space are reduced, working efficiency is superior and judgment accuracy is high.
In order to achieve the above-mentioned object, the present invention provides a method for inspecting appearance and shape of a subject body, comprising: lighting a linear portion of the subject body with a first slit light, taking a picture of the linear portion lighted by the first slit light with a first picture taking means to obtain appearance data, lighting the linear portion with a second slit light, taking a picture of the linear portion lighted by the second slit light with a second picture taking means to obtain shape data, and judging quality of appearance and shape of the subject body based on the appearance data and the shape data.
Since a quality in respect of appearance and shape of a subject body is judged from appearance data and shape data of the same linear portion of the subject body, respective disadvantages of judgments by the appearance data and the shape data are compensated each other. Since appearance data and shape data of the same linear portion are obtained simultaneously, the both data can be compared with each other easily, so that even if judgment is delicate by one of the both data, a clear judgment is possible by comparing the both data with each other and judgment accuracy is improved greatly.
Since the first picture taking means and the second picture taking means take pictures of the same linear portion of the subject body simultaneously, picture taking mechanisms by the line camera and the area camera can be integrated to reduce installation cost and space and maintain high working efficiency.
In the above method for inspecting appearance and shape of a subject body, the second picture taking means may be an area camera.
Shape data for judging unevenness of a surface of the subject body can be obtained by the area camera.
In the above method, the first picture taking means may be a line camera.
Appearance data for judging appearance of a surface of the subject body can be obtained by the line camera.
In the above method, the first picture taking means may be a color line camera.
Appearance data of the subject body can be obtained as color data by the color line camera and quality of the subject body can be judged easily with the colored appearance picture.
In the method, the first picture taking means may be a three color process line camera.
With the three color process line camera, respective appearance data of primary colors BGR can be obtained to facilitate more accurate judgment of the quality.
In the method, wave length of the first slit light and wave length of the second slit light may be different from each other, the first picture taking means may have a filter admitting only the first slit light, and the second picture taking means may have a filter admitting only the second slit light.
Since respective wave lengths of the first and second slit lights are different from each other, the both slit lights are prevented from interfering with each other. And the first and second picture taking means have respective filters admitting only corresponding slit light, so that appearance data and shape data not influenced by each other can be obtained to improve judgment accuracy.
The invention also provides, a method for inspecting appearance and shape of a subject body, comprising: lighting a first linear portion of the subject body with a first slit light, taking a picture of the first linear portion with a first picture taking means to obtain appearance data, lighting a second linear portion slightly shifted from the first linear portion with a second slit light, taking a picture of the second linear portion with a second picture taking means to obtain shape data, the lighting and taking picture of the second linear portion being carried out simultaneously with the lighting and taking picture of the first linear portion, and judging quality of appearance and shape of the subject body based on the appearance data of the first linear portion and the shape data of the second linear portion.
Since the first slit light and the second slit light light different linear portions and the first picture taking means and the second picture taking means take respective corresponding pictures of the linear portions, the first and second picture taking means necessitate no filter for selecting an incident light.
The slight deviation of the position of the second linear portion which is taken a picture by the second picture taking means from the position of the first linear portion which is taken a picture by the first picture taking means, can be corrected by data processing, to obtain appearance data and shape data in respect of the same linear portion which can compensate each other and can be compared with each other. Therefore, a high judgment accuracy can be maintained without mutual interference of the lights.
According to another aspect of the present invention, there is provided an apparatus for inspecting appearance and shape of a subject body, comprising: a first light projecting means for projecting a first slit light onto the subject body, a first picture taking means for taking a picture of a linear portion of the subject body lighted by the first slit light to obtain appearance data, a second light projecting means for projecting a second slit light onto the linear portion of said subject body, a second picture taking means for taking a picture of the linear portion lighted by the second slit light to obtain shape data, and a judgment means for judging quality of appearance and shape of the subject body based on the apparatus data and the shape data.
Since the judgment means judges quality of appearance and shape of the subject body based on the appearance data and the shape data of the same linear portion of the subject body, respective disadvantages of judgments by the appearance data and the shape data are compensated each other. Since appearance data and the shape data of the same linear portion are obtained simultaneously, the both data can be compared with each other easily, so that even if judgment is delicate by one of the both data, a clear judgment is possible by comparing the both data with each other and judgment accuracy is improved greatly.
Since the first picture taking means and the second picture taking means take pictures of the same linear portion of the subject body simultaneously, picture taking mechanisms constituting the first picture taking means and the second picture taking means can be integrated to reduce installation cost and installation space and maintain high working efficiency.
Further, the present invention provides an apparatus for inspecting appearance and shape of a subject body, comprising: a first light projecting means for projecting a first slit light onto the subject body, a first picture taking means for taking a picture of a first linear portion of the subject body lighted by the first slit light to obtain appearance data, a second light projecting means for projecting a second slit light onto a second linear portion of the subject body slightly shifted from the first linear portion, a second picture taking means for taking a picture of the second linear portion lighted by the second slit light to obtain shape data, and a judgment means for judging quality of appearance and shape of the subject body based on the appearance data of the first linear portion and the shape data of the second linear portion.
The first slit light and the second slit light light different linear portions and the first picture taking means and the second picture taking means take respective corresponding pictures of the linear portions, namely the first and second picture taking means admit either one of the first and second slit lights respectively. Therefore, the first and second picture taking means necessitate no filter for distinguishing and selecting a incident light.
The slight deviation of the position of the second linear portion which is taken a picture by the second picture taking means from the position of the first linear portion which is taken a picture by the first picture taking means, can be corrected by data processing, to obtain appearance data and shape data in respect of the same linear portion which can compensate each other and can be compared with each other. Therefore, a high judgment accuracy can be maintained without mutual interference of the lights.